Is it possible for a phone to be infected without any attack vector?

I have a Samsung Galaxy S10+ Exynos on Android 12. For months, my phone was slow, super hot, and crashing a lot whenever I connected to WiFi. I formatted the phone several times. After that, I decided to install Bitdefender on my phone (paid). After formatting the phone and installing Bitdefender, my phone stopped crashing, heating up, and slowing down. The question I wanted to ask is if a phone can be infected without any attack vector, just by connecting to WiFi (which I think was the reason for the infection). I didn't install anything from outside the Play Store and this always happened to my phone.